From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx195.postini.com [74.125.245.195]) by kanga.kvack.org (Postfix) with SMTP id 6766F6B004D for ; Tue, 15 May 2012 07:03:21 -0400 (EDT) Date: Tue, 15 May 2012 13:03:02 +0200 From: Johannes Weiner Subject: Re: [patch 0/6] mm: memcg: statistics implementation cleanups Message-ID: <20120515110302.GH1406@cmpxchg.org> References: <1337018451-27359-1-git-send-email-hannes@cmpxchg.org> <4FB1A115.2080303@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4FB1A115.2080303@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: Andrew Morton , Michal Hocko , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, May 15, 2012 at 09:19:33AM +0900, KAMEZAWA Hiroyuki wrote: > (2012/05/15 3:00), Johannes Weiner wrote: > > > Before piling more things (reclaim stats) on top of the current mess, > > I thought it'd be better to clean up a bit. > > > > The biggest change is printing statistics directly from live counters, > > it has always been annoying to declare a new counter in two separate > > enums and corresponding name string arrays. After this series we are > > down to one of each. > > > > mm/memcontrol.c | 223 +++++++++++++++++------------------------------ > > 1 file changed, 82 insertions(+), 141 deletions(-) > > to all 1-6. Thank you. > > Acked-by: KAMEZAWA Hiroyuki Thanks! > One excuse for my old implementation of mem_cgroup_get_total_stat(), > which is fixed in patch 6, is that I thought it's better to touch all counters > in a cachineline at once and avoiding long distance for-each loop. > > What number of performance difference with some big hierarchy(100+children) tree ? > (But I agree your code is cleaner. I'm just curious.) I set up a parental group with hierarchy enabled, then created 512 children and did a 4-job kernel bench in one of them. Every 0.1 seconds, I read the stats of the parent, which requires reading each stat/event/lru item from 512 groups before moving to the next one: 512stats-vanilla 512stats-patched Walltime (s) 62.61 ( +0.00%) 62.88 ( +0.43%) Walltime (stddev) 0.17 ( +0.00%) 0.14 ( -3.17%) That should be acceptable, I think. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org